Electron energies of weakly ionized plasmas under alternating electric fields

1984 ◽  
Vol 26 (3) ◽  
pp. 585-587 ◽  
Author(s):  
W L Harries
MRS Bulletin ◽  
1991 ◽  
Vol 16 (2) ◽  
pp. 16-22
Author(s):  
David B. Graves ◽  
Richard A. Gottscho

In manufacturing microelectronic and optoelectronic devices, thin solid films of various sorts are routinely deposited and etched using low pressure, weakly ionized plasmas. The term “plasma” in this context implies an ionized gas with nearly equal numbers of positive and negative charges. This definition is not very restrictive, so. there are an enormous number of phenomena that are termed plasmas. For example, very hot, magnetized, fully ionized plasmas exist in stellar environments and thermonuclear fusion experiments. High temperature electric arcs are a form of plasma as well. In contrast, the plasmas used in electronic materials processing are near room temperature and the gas is usually weakly ionized. Indeed, due to the sensitivity of electronic devices to high temperatures, their low operating temperature is one of the major advantages of plasma processes.Plasma processing is attractive because of two important physiochemical effects: energetic free electrons in the plasma (heated by applied electric fields) dissociate the neutral gas in the plasma to create chemically reactive species; and free positive ions are accelerated by the plasma electric fields to surfaces bounding the plasma. Reactive species created in the plasma diffuse to surfaces and adsorb; wafers to be processed are typically placed on one of these surfaces.The combination of neutral species adsorption and positive ion bombardment results in surface chemical reaction. If the products of the surface reaction are volatile, they leave the surface and etching results. If the products are involatile, a surface film grows.


AIAA Journal ◽  
1998 ◽  
Vol 36 ◽  
pp. 816-822
Author(s):  
Igor V. Adamovich ◽  
Vish V. Subramaniam ◽  
J. W. Rich ◽  
Sergey O. Macheret

2001 ◽  
Vol 87 (16) ◽  
Author(s):  
Richard A. Gray ◽  
Oleg A. Mornev ◽  
José Jalife ◽  
Oleg V. Aslanidi ◽  
Arkady M. Pertsov

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1398
Author(s):  
Yong-Qi Zhang ◽  
Xuan Wang ◽  
Ping-Lan Yu ◽  
Wei-Feng Sun

Trimethylolpropane triacrylate (TMPTA) as a photoactive crosslinker is grafted onto hydrophobic nanosilica surface through click chemical reactions of mercapto double bonds to prepare the functionalized nanoparticles (TMPTA-s-SiO2), which are used to develop TMPTA-s-SiO2/XLPE nanocomposites with improvements in mechanical strength and electrical resistance. The expedited aging experiments of water-tree growth are performed with a water-knife electrode and analyzed in consistence with the mechanical performances evaluated by means of dynamic thermo-mechanical analysis (DMA) and tensile stress–strain characteristics. Due to the dense cross-linking network of polyethylene molecular chains formed on the TMPTA-modified surfaces of SiO2 nanofillers, TMPTA-s-SiO2 nanofillers are chemically introduced into XLPE matrix to acquire higher crosslinking degree and connection strength in the amorphous regions between polyethylene lamellae, accounting for the higher water-tree resistance and ameliorated mechanical performances, compared with pure XLPE and neat-SiO2/XLPE nanocomposite. Hydrophilic TMPTA molecules grafted on the nano-SiO2 surface can inhibit the condensation of water molecules into water micro-beads at insulation defects, thus attenuating the damage of water micro-beads to polyethylene configurations under alternating electric fields and thus restricting water-tree growth in amorphous regions. The intensified interfaces between TMPTA-s-SiO2 nanofillers and XLPE matrix limit the segment motions of polyethylene molecular chains and resist the diffusion of water molecules in XLPE amorphous regions, which further contributes to the excellent water-tree resistance of TMPTA-s-SiO2/XLPE nanocomposites.


2021 ◽  
Vol 22 (1) ◽  
pp. 394
Author(s):  
Simone Krueger ◽  
Alexander Riess ◽  
Anika Jonitz-Heincke ◽  
Alina Weizel ◽  
Anika Seyfarth ◽  
...  

In cell-based therapies for cartilage lesions, the main problem is still the formation of fibrous cartilage, caused by underlying de-differentiation processes ex vivo. Biophysical stimulation is a promising approach to optimize cell-based procedures and to adapt them more closely to physiological conditions. The occurrence of mechano-electrical transduction phenomena within cartilage tissue is physiological and based on streaming and diffusion potentials. The application of exogenous electric fields can be used to mimic endogenous fields and, thus, support the differentiation of chondrocytes in vitro. For this purpose, we have developed a new device for electrical stimulation of chondrocytes, which operates on the basis of capacitive coupling of alternating electric fields. The reusable and sterilizable stimulation device allows the simultaneous use of 12 cavities with independently applicable fields using only one main supply. The first parameter settings for the stimulation of human non-degenerative chondrocytes, seeded on collagen type I elastin-based scaffolds, were derived from numerical electric field simulations. Our first results suggest that applied alternating electric fields induce chondrogenic re-differentiation at the gene and especially at the protein level of human de-differentiated chondrocytes in a frequency-dependent manner. In future studies, further parameter optimizations will be performed to improve the differentiation capacity of human cartilage cells.


2012 ◽  
Vol 85 (3) ◽  
Author(s):  
Zhong-Qiang Liu ◽  
Guang-Cai Zhang ◽  
Ying-Jun Li ◽  
Su-Rong Jiang

1991 ◽  
Vol 19 (6) ◽  
pp. 1090-1113 ◽  
Author(s):  
M.W. Blades ◽  
P. Banks ◽  
C. Gill ◽  
D. Huang ◽  
C. LeBlanc ◽  
...  

2010 ◽  
Vol 27 (4) ◽  
pp. 049901
Author(s):  
Dimitris J Panagopoulos ◽  
Andreas Karabarbounis ◽  
Lukas H Margaritis

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